1) Field of the Invention
The invention herein relates to recreational vehicles, specifically an improved steerable scooter.
2) Description of the Prior Art
The structure of conventional steerable vehicles, as shown in FIG. 1, is typically comprised of a handlebar 11 and a caster member 12 respectively disposed at the top and bottom ends of a front stem 10, the said caster member 12 extending towards the back and having a front wheel 13 installed on each of its two sides, a rear tube 20 having a rear wheel 21 on each of its two ends, a frame 30 conjoined between a head tube 14 and the rear tube 20, and a saddle 40 mounted on the frame 30. After the rider is seated on the saddle 40, both hands are used to turn and control the handlebar 11, thus the said caster member 12 and two front wheels 13 which are disposed on it can be steering coordinately, prompting the movement of the two front wheels 13 to the left and right and causing the said rear wheels 21 to follow such that the entire vehicle proceeds on a course determined by the rider. While it cannot be denied that the control approach of such an arrangement effectively provides for children""s riding and operation, the following shortcomings still await improvement:
1. Referring to FIG. 2, the purpose of the two said front wheels 13 as well as the two rear wheels 21 is to provide four points of ground contact in perfect balance while the steerable vehicle travels forward in straight line; when the handlebar 11 is turned, the inner side of the front wheel 13xe2x80x2 is closer to the frame 30 and arrayed with the two rear wheels 21 into a balanced triangular formation; however, it is known that when the two front wheels 13 are turned in the opposite direction by the handlebar 11, a greater amount of turning friction is generated due to the simultaneous ground contact of the said two wheels 13, requiring more strength to operate the handlebar 11 and causing it to be more unresponsive.
2. Since the said two front wheels 13 are respectively situated at the two sides of the frame 30, as the individual wheels contact the ground when the road surface is irregular, the front wheels 13 and the two rear wheels 21 do not individually contact the ground in an evenly arrayed isosceles or equilateral triangle such that the steerable vehicle easily slides and is unstable.
3. Since the said two front wheels 13 are disposed on one extremity of the caster member 12 and situated at the rear extent of the front stem 10, when the front wheels 13 are turned to any particular side, the opposite extremity of the caster member 12 is suspended off the ground and unsupported; this state has no affect while the steerable vehicle proceeds in a straight line, but when the rider applies force towards the suspended side to change direction, center of gravity instability often results in dangerous slide outs.
4. Since such steerable vehicles are only capable of carrying and being operated by small younger children, they are not suitable for larger children, teenagers, and older people and, as such, have limited recreational and application value.
In view of the above situation, some manufacturers have introduced an improved steerable vehicle which, as shown in FIG. 3, consists of a caster member 12 at the lower extent of a front stem 10 having an assisting wheel 15 at one extremity that is slightly higher than two front wheels 13, wherein the assisting wheel 15 and the two front wheels 13 at the rear extent are arranged in a triangular formation that is narrow at the anterior and wide at the posterior such that when the handlebar 11 executes a turn and leans in the direction of the said turn, the said assisting wheel 15 serves as a support point that is present at the appropriate time to prevent lateral slide outs. Such an improvement undoubtedly enhances usage and safety, but since the said assisting wheel 15 is situated at the lower extent of the front stem 10 and the center of gravity is situated off to the side of the change in direction and not at the exact lower extent of the front stem 10 when the handlebar 11 is turned, therefore, while the placement of the said assisting wheel 15 effectively prevents lean during small angle turns by the handlebar 1, it is still incapable of counteracting lean when large angle turns are executed. Additionally, given that the handlebar 11 of the conventional steerable vehicle requires more physical effort to control, is less responsive, tends to lose traction on uneven road surfaces, is unstable, and of limited practical application, the improvement effected is not significant enough to make a difference.
The primary objective of the invention herein is to provide an improved steerable scooter, wherein a single front wheel for turning and inclination as well as two rear wheels constantly contact the ground simultaneously in a three-point supportive formation to provide for optimal stability and responsiveness due to reduced friction when turns are executed by the said steerable scooter.
Another objective of the invention herein is to provide an improved steerable scooter, wherein assisting wheels are installed on two sides at the bottom end of a rearwardly inclined front stem that are marginally higher than and simultaneously articulated with the front wheel and since the front wheel at the rear extent forms a triangular formation that is wide at the anterior and narrow at the posterior, when the handlebar is turned for a larger angle, the said assisting wheel on the side of the turn affords ground contact support at the appropriate time, thereby enhancing utilization safety by effectively preventing slide outs due to excessive lean.
Yet another objective of the invention herein is to provide an improved steerable scooter, wherein a freely adjustable and removable saddle is installed on the frame and the two rear wheels are equipped with a synchronized brake mechanism to allow safe riding and, furthermore, the option of enjoying the scooter of the present invention while seated or standing on one foot, thereby effectively widening its scope of application.